The present invention generally relates to microelectronic devices. More particularly, the present invention relates to apparatus and techniques for distributing power to microelectronic devices.
Regulators are often employed to provide a desired, regulated power to microelectronic devices such as microprocessors. For example, switching regulators such as buck regulators are often used to step down a voltage (e.g., from about 3.3 volts) and provide suitable power to a microprocessor (e.g., about 10-30 amps at about 2-3 volts).
To increase speed and reduce costs associated with microprocessors, microprocessor gate counts and integration generally increase, while the size of the microprocessor per gate generally decreases. As gate counts, speed, and integration of microprocessors increase, supplying requisite power to microprocessors becomes increasingly problematic. For example, a current required to drive the processors generally increases as the number of processor gates increases. Moreover, as the gate count increases per surface area of a processor, the operating voltage of the processor must typically decrease to, among other reasons, reduce overall power consumption of the processor. Furthermore, as the microprocessor speed increases, the microprocessor demands the higher current at faster speeds. In addition, because one regulator generally supplies power to the entire microprocessor, the single regulator must supply the higher current power at higher speeds to the entire microprocessor.
Although buck regulators are generally suitable for controlling power to some microprocessors, such regulators are not well suited to supply relatively high current (e.g., greater than about 30 amps) at relatively high speed (e.g., greater than about 500 MHz.). One reason that buck regulators have difficulty supplying high current at high speed to the microprocessor is that the current supplied from the regulator to the processor has to travel a conductive path that generally includes a portion of a printed circuit board that couples the processor to the regulator. The relatively long conductive path between the processor and the regulator slows a speed at which the regulator is able to supply current to the processor. In addition, as microprocessor speed and current demands increase, the buck controller simply cannot provide the desired amount of current within the desired amount of time. Thus, as microprocessor gate counts and clock speeds increase, improved methods and apparatus for supplying high current at high speed and low voltage are desired.
The present invention provides improved apparatus and techniques for regulating power to a microelectronic device. More particularly, the invention provides improved devices and methods suitable for supplying electronic devices with relatively high, regulated current at relatively high speed.
The way in which the present invention addresses the deficiencies of now-known regulators and power supply systems is discussed in greater detail below. However, in general, the present invention provides an array of power regulators that provides power to a single microelectronic device.
In accordance with one exemplary embodiment of the present invention, an array of regulators is configured to provide power to a microprocessor. In accordance with one aspect of this embodiment, the array is formed as an integrated circuit on a semiconductor substrate. In accordance with a further aspect of this embodiment, the circuit is coupled to the microprocessor through a relatively short conductive path (e.g., by coupling the circuit to the device via bump interconnects). In accordance with yet a further aspect of this embodiment, the array circuit is formed on a compound semiconductor substrate such as a silicon germanium (SiGe) substrate to facilitate faster current supply to the device.
In accordance with a further exemplary embodiment of the present invention, a pass band filter is coupled to a regulator within the array. In accordance with one aspect of this embodiment, the array is capable of providing various amounts of current at various frequencies to portions of a microelectronic device. This allows portions of the array to rapidly respond to high frequency power demands of a potion of a microprocessor and supply relatively high current to other portions of the microprocessor which have a lower frequency power demand.